voltage across capacitor

Discussion in 'General Electronics Discussion' started by bhuvanesh, Apr 14, 2014.

1. bhuvanesh

201
0
Aug 29, 2013
i dont know how voltage across r1 is equal to voltage across c since c and r2 are in series

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2. LvW

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Apr 12, 2014
R1 is in parallel to the voltage source. Thus, the voltage across r1 is identical to the source voltage V1 (12 V).
The voltage across C1 is nearly identical to the source voltage due its very large parallel loss resistance - in parallel with the instrument´s input resistance..

Last edited: Apr 14, 2014
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3. (*steve*)¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥdModerator

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Jan 21, 2010
What current flows through R2?

Therefore, what is the voltage drop across R2?

Therefore what is the voltage across C1?

Consider the steady state condition after the circuit has been left sitting like this for some time...

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4. bhuvanesh

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Aug 29, 2013
what i want to know is.doesnt R2 contribute any voltage drop.

5. dcac

56
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Jul 10, 2013
R2 does contrribute to the the voltage across the capacitor. However, R2 is responsible for the time that takes to charge up to the voltage.

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6. bhuvanesh

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Aug 29, 2013
why R2 doesnt contribute any voltage.why?

capacitor blocks dc current since the R2 is in series with capacitor.it does allow any current to pass through so no voltage drop across R2. am i right

7. dcac

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1
Jul 10, 2013
yes you are right

8. Harald KappModeratorModerator

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Nov 17, 2011
Take heed of Stev's advice:
Conversely: look at the voltage across R2 when you turn on V1 initially (after C1 has been discharged). Here is a lesson that explains the effect.

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9. bhuvanesh

201
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Aug 29, 2013
thanks for the ppt.i am stating what i read from that ppt.correct me if i am wrong
1)till the capacitor being fully charged there is some flow of current through R2.
2)charging and discharging upto time constant is only depends on R and C,whereas the transient period and steady state are not
sorry if i am wrong

10. Harald KappModeratorModerator

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Nov 17, 2011
1 is o.k.
2:
Charging and discharging is the transient period. Therefore only the voltage in steady stae is independent from R and C, the voltage during the transient time is dependent on R and C.

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11. bhuvanesh

201
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Aug 29, 2013
thank you so much.i am clear.do u any one know is there something like chating to get instant answer than rather placing it in forum and waiting for a while.